Broaching machine



Sept. 18, 1945. w

BROACHING MACHINE Filed June 21, 1943 5-She etsSheet 1 .z/vz/v m 77.Maze M8256.

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a Q 4 m. V 8 a w 8 m l ln ll a p Hm fa U i u Sept. 18, 1945. B. WELTEBROACHING MACHINE- File d June 21, 1943 S'SheetS -Sheet 4 Q INVENTOR.

a i M d 1 M Sept. 8, 1945. B. wELTE 2,385,119

BROACHING MACHINE Filed June 21, 1943 5 Sheets-Sheet 5 I BY 7 I tions.

Patented Sept. 18, 1945 UNITED STATES 'ATENT' OFFICE 2,385,119 BROACHINGMACHINE Benedict Welte, Lake orionrownsili Oakland County, MiClL,assignor to Colonial Broach Company, Detroit, Mich., a.

aware corporation of Del- 1 14 Claims.

The present invention relates to a surface broaching machine of the typeadapted to make a plurality of successive cuts on a single workpiecewith the same broaching tool, and is a continuation-in-part ofapplicants copending application, Serial No. 478,508, filed March 9,1943. It is the general object of the present invention to provide animproved hydraulic circuiti for operating and controlling the movementsof the broach and the work holding fixture, or table, during thesuccessive broaching opera- More specifically, it is an object of thepresent invention to provide automatically operable hydraulic means toreciprocate the broach through a predetermined number of breaching andbreach return strokes and at the same timeadvance the work table tobreachin position at the end of each broach return stroke and retractthe table at the end of each broaching stroke.

Another object of the invention is to provide an improved hydraulic andmechanical indexing mechanism for controlling the operation of themachine through a predetermined number of cycles and then bringing themachine to a stop.

Another object of the invention is to provide improved and simplifiedmeans in an automatic multiple stroke broaching machine for controllingthe operation of the machine in such a manner that the broaching ramtakes a plurality of roughing strokes followed by a single finishingstroke of greater length than the roughing strokes in order that thefinishing teeth of the breach will not contact the work except upon thefinishing operation.

Other objects and advantages of the invention will become apparent fromthe following specification, the drawings relating thereto, and from theclaims hereinafter set forth.

In the drawings, in which like numerals are used to designate like partsin the several views throughouti Figurev 1 is a front elevation of avertical broaching machine to which the invention may be applied Figure2 isa side view of the breaching machine shown in Figure 1;

Figure 3 is a fragmentary sectional view' taken onthe line 3-3 of Figure1, showing a plan view of the work moving fixture;

Figure is a sectional view, the upper portion of which is taken on theline 4-4 of Figure 3 and the lower portion of which is taken on thecenter line of the machine as indicated by the line 4-4 in Figure 7;

.machine, showing the location of the trip dogs Figure 5 is a sideelevation of the work supporting fixture and adjustable abutment mountedon the table;

Figure 6 is a view similar to Figure 5, showing the parts in adifierent'position;

Figured is a view taken on the line 1-1 of Figure 4; v

Figure 8 is a fragmentary section taken on the line 8-,8 of Figure 3; r

Figures 9, 10 and 11 show the form of workpiece for which the particularembodiment of the invention illustrated is constructed;

Figure 12 is a hydraulic circuit diagram show ing the hydrauliccircuitcontrolsand cylinders provided to effect automatic operation of themachine through a complete cycle of breaching strokes;

Figure' l3 is' a view corresponding to Figure 5, showing amodification-of the invention incorpolrating'means for effecting afulllength stroke of the broaching ram only on the finishing stroke ofthe cycle;

Figure 14 is a fragmentary sectional view taken onthe line i4f'l4 ofFigure 13; and

Figure 15 is a partial front elevation of the on the main breaching ramwith part of the work fixture broken away to show the lower trip dog.

. Referring to the drawings, the invention is shown applied to avertical breaching machine having a main frame l0 and a verticallymovable breaching slide H, which is formed integrally with a hydrauliccylinder [2 which is reciprocated with reference to. a stationary pistonunder the control of .the hydraulic circuit hereinafter described.Mounted on the slide l is a face plate l2 carryingapair oftool' holdingchannel-shaped members [3. In the present instance, the machine isdesignedlfor operating upon two workpieces simultaneously and forsimultaneously cutting two relatively deep notches'in each of theworkpieces. Consequently, the tool holdingchannels support fourbroaching tools I 4.,

The framof the machine includes a forwardly projecting portion having atop surface l5 defining a horizontal slide on which is mounted the workmoving and supporting table 16. A pair of retaining plates il I locatedat opposite sides of the work table are fixed tov the top surface 15 ofthe frame andoverlie the edges of the work table I6 to retain the tablein position while permitting it to reciprocate toward and from thebroach.

The. top frame member ['5 contains a longitudinally extending slot #8 atits center, into which projects a downwardly'ex'tending rib IS on thetable 16. J ournaled in a sleeve on the table is a centrally locatedvertical pin 2|, the lower end of which is formed into a rectangularshoe 22 which lies below the bottom surface of the rib i9 and also belowthe bottom surface of the member 15 of the frame. The shoe 22, which isof hardened steel, fits in a hardened steel cam groove 23 formed in atransverse slide 24, which is mounted in suitable ways 25 on theunderside of the frame member I5 for movement transverse to the movementof the table 16. The slot 23 is diagonal, as best shown by dotted linesin Figure 3, in consequence of which transverse reciprocation of theslide 24 efiects longitudinal reciprocationof the table l6. Suchtransverse reciprocation of the slide 24 is effected by a movablecylinder 26, which is keyed to the slide 24 by key 21 and which slidesupon a pair of aligned stationary piston rods 28 and 29 fixed to theframe of the machine.

The arrangement of the means for reciprocating the table so fardescribed is substantially like that disclosed in applicant's Patent No.2,225,191 except that the cam groove in the present instance isstraight, rather than arcuate, and the angle of the cam groove 23 in thepresent construction is such an angle that the force exerted on thetable by the broach will not be effective to cause movement of the slide24 against the minimum pressure exerted by the table moving piston andcylinder regardless of the position of the shoe 22 in the groove 23.

A work holding fixture is mounted upon the table 16 and includes meansfor locating the position of the table during the broaching operations.v

This fixture comprises a main casting, indicated generally at 30. Thecasting 31) includes a fiat base portion 3| secured to the table 16 inany suitable manner, as by bolts 32, and-a pair of transversely alignedbosses 33 and 34, the outer ends of which are enlarged to form housings35 and 36, respectively. The casting also includes a pair oflongitudinally extending housings 31 and 3B in longitudinal alignmentwith the housings and 36, respectively, and projecting rearwardlytherefrom. It'will be noted from Figures 3 and '7 that the housings 31and 38 extend outwardly at the sides beyond the side edges of the baseportion 3| of the casting 30, thereby defining a pair of side recessesbeneath the housings 31 and 3B. The casting also includes an upstandingwork locating block 39, which is of generally T shape, as viewed in planin Figure 3, and a pair of reinforcing ribs 40 and 4| extending betweenthe work supporting member 39 and the bosses 33 and 34, respectively.The work supporting member, or block, 39 is provided with two rightangle notches in its forward corners, as best shown in Figure 3, toreceive a pair of workpieces 44. Suitable hardened steel wear plates aresecured to the sides of the right angle notches to form the workpiecelocating surfaces.

The workpiece, as best shown in Figures 9, 10 and 11, is of generallyrectangular configuration except that it has an arcuate or semicirculargroove 45 in its'upper surface. The particular operation to be performedon the workpiece by the machine illustrated is a notching operationinthe forward corners to form notches 46, the metal to be removed beingindicated by the dotted lines in Figure" 11.

Each workpiece is held in'position after it is seated against the wearplates 45 by means of a clamp 48, of generally right angle configurationwith its downwardly extending leg 49 arcuately curved to fit thesemicircular groove, or channel, 45. The clamp is held in position bymeans of a stud 50 secured in the bottom of a recess 5| in the top ofmember 39 and extending through a suitable opening in the clamp 48. Theclamp is tightened by means of a nut 52 and a spring 53 surrounds thestud and tends to urge the clamp upwardly to facilitate release thereof.

It will be understood that the present invention is not limited in itsapplication to the particular operation illustrated or to any particularform of workpiece, and that suitable means may be provided to hold anyform of workpiece on the broaching machine.

Fixed to the upright portion of the frame of the machine at each side ofthe broaching slide are fixed abutments 56 which may be held in positionin any suitable manner; as by bolts 51. One of the fixed abutments 56has a longitudinal opening 58 extending therethrough in which isslidably mounted a push rod 59, for a purpose hereinafter described.

When the table I6 advances with the work supporting fixture, one end ofeach of a pair of rods 66 carried by the fixture is adapted to abutagainst the fixed abutments 56, respectively, and limit further movementof the table and workpiece toward the broach.

The rods 60 are rectangular in cross section and are slidable inrectangular slots 6| in the housings 31 and 38 of the fixture casting30. The slots 6| in the housings 31 and 38 are closed by means of a pairof plates 63 and 64', the forward ends of which are enlarged to completethe walls of the housings 35 and 36, respectively.

The bottoms of the slots 6| are provided with suitable slots 66, as bestshown in Figure 4, to receive pins 61 which are fixed, respectively, inthe rods 60. Coil springs 68 connect the pins 61 to stationary pins 69,thus normally urging the pins 61 and, consequently, the rods 60 to theleft, as viewed in Figure 4, the slots 66 permitting such movement.

A pair of stationary stops 10 secured to the stationary retaining plates11 limits maximum movement of the pins 61 and rods 60 to the left, asviewed in Figure 4, to the position shown in that figure. In thisposition, the rods 60 are out of contact with the abutments 56, thuspermitting the push rod 59 to project from its abutment 56.

Means are provided on the fixture for automatically controlling theposition of the rods 69 in order to limit movement of the work tabletoward the broach. The means includes a relatively heavy shaft 12journaled in the two bosses 33 and 34 extending transversely to thetable I6. The ends of the shaft 12 project into the housings 35 and 36,where they are reduced in diameter, as indicated at 13, and receive apair of rotatable abutment elements 14. The two abutment elements, whichare identical in construction, are keyed to'the shaft 12 by means of akey 15 and are peripherally formed of a plurality of stepped fiatsurfaces 16, 11, 18, 19, 80, 81, 82, 83, 64, 65, 86 and 81,circumferentially distributed in sequence around the periphery and ofprogressively decreasing distance from the aids of the shaft 12. Thesurfaces are so arranged that upon rotation of the shaft 12 any one ofthe fiat surfaces 16 to 81, inclusive, may be brought into position toabut against the ends of rods 60. In this connection, it will be notedthat the rods 60 extend in a line intersecting the axis of the shaft 12and, consequently, no pressure exerted between th rods 60 and any one ofthe surfaces 16 to 8I,inclusive, will have a tendency to rotate theabutment elements 14.

The right-hand end of shaft I2, as viewed in Figure '7, beyond therotatable abutment element 14 thereon, is still further reduced indiameter, as indicated at 90, to receive a ratchet wheel 92, shown bestin Figure 4. The ratchet wheel is locked in position on the shaft I2 byany suitable means, such as washer 93 and a nut 94, which is threaded onthe extremity of the shaft I2. The opposite end of the shaft I2 is notprovided with a corresponding ratchet wheel, but the abutment element I4on the opposite end is held against displacement by a pair of washers 95and 96 and a nut 9! on the end of shaft I2.

Means are provided for engaging the ratchet 92 and automaticallyindexing the shaft I2 on each reciprocation of the work table I6. Thismeans includes an L-shaped block I fixed in any suitable manner, as bycap screws IN, to the right-hand stationary retaining plate I! on oneside of the right-hand edge of housing 36. Slidably mounted on block I00is a pawl carrier I03 which may be adjusted in position longitudinallyof the plate I! by means of an adjusting screw I04 threaded in theupstanding leg of the L-shaped block I00. The pawl carrying block I03may be held in adjusted position by means of a stud I05, which extendsthrough a slot I06 in the pawl carrier I03 and is secured in the blockI00.

The pawl I08 is pivoted on member I03 by means of a stud I09 held inposition by a pair of nuts. The pawl I08 lies in a recess I I0 formed onthe inner side of the pawl carrier I03. A

suitable spring III, shown best in Figure 4, is,

provided for normally urging the pawl in an upward direction to engagethe ratchet wheel 92. It will be apparent that as a result of thisconstruction when the table I6 withdraws from'the broach the pawl I08will engage a tooth of the ratchet wheel and index the ratchet wheel onenotch in a counterclockwise direction, as viewed in Figures 4, 5 and 6.r I

The cover plate 64 for the housing 36 is cut away at I I2 to make roomfor the block I00 and pawl carrier I03 whenthe table withdraws frombroaching position to the position shown in Figure 4. As best shown inFigure 8, a spring pressed detent H0 is provided in boss 34 and isadapted to engage in any one of a plurality of notches II I in the shaftI2 for retaining the shaft against accidental displacement from any oneof its plurality of indexed positions. One notch is provided for each ofthe flat surfaces I6 to 81, inclusive, on the rotatable abutment membersI4.

The mechanism operates in the following manner. The starting position ofthe machine is illustrated in Figure 4, in which position the work tableI6 is fully withdrawn from broaching position and the ratchet pawl I08has just completed indexing of the rotatable abutments I4 to return themto the position they assume at the start of the broaching cycle. In thatposition, flat surfaces I6 on the abutments I4 are in position to engagethe plunger 60'but are actually out of contact with the plunger byreason of the fact that movement of the plunger 60 to the left, asviewed in Figure 4. is limited by engagement between pins 61 and thestationary stops I0. In this position of the parts, a dog II8 on arearward projection of the table I6 has engaged a lever I I9, which ispivotally mounted upon a stationary bracket I20, and shifted the leverH9 in a counterclockwise position, thereby causing the lever to forcethe rod I2I to the right, as viewed in Figure 4. The rod I2I actuates acontrol valve, hereinafter described, which effects return of thebroaching cylinder and broach to theirupper or starting positions, shownin Figure 4.

' As soon as the broach reaches its upper position, the machineautomatically stops to permit insertion of the work in the fixture. Whenthis is done, the machine is started and the first movement is amovement of the work table toward the broach. During such movement, thefiat surfaces I6 on the rotatable abutments I4 engage the'ends of therods 60 and force the rods rearwardly against the stationary abutments56, thereby limiting movement of the table toward the broach. In view ofthe fact that the table is driven by means of a hydraulic cylinderthrough self-locking cam groove 23, the cylinder will wedge the table inbroaching position with the plunger 60 forced tightly against thestationary stops 56.

Since the driving connection between the cylinder 25 and the table I6 islocated centrally of the table and between the stationary abutments 56,the wedging action will positively prevent cooking of the table underany of the loads to which it is subject during the broach cuttingoperation.

Completion of this forward movement of the table will cause the push rod59 in the stationary abutment 56 to be movedto the right, as viewed inFigure l. to the position shown in Figure 5, and the push rod isconnected to a suitable control valve,- hereinafter described, whichinitiates the downward 0r broach cutting stroke of the broachingeylinderand broaches I4. The rod 59 is also mechanicallyccnnected to rodI 2| in such a manner that upon movement of the rod 59 into its abutment56 the lever II9 will be swung in a clockwise direction from theposition shown in Figure l, as hereinafter described in greater detail.Onthis first downward movement of the breaches, the broach cuttingoperation is performed on the workpieces. When the broaches reach thebottom of their downward and broaching stroke, suitable valve means areoperated to move the cylinder 26 to the left, as viewed in Figure '7, inorder to retract the table to the position shown in Figure 4; Upon suchretraction, the pawl I08 indexes the rotatable abutments I4 to aposition in which the flat surfaces 11 are in alignment with the rods60.

' The table return movement also returns lever H9 to the position shownin Figure 4, thereby causing return of the broaches to their upperposition. The table then makes its second advancing movement, this timemoving a slightly greater distance than before due to the fact that theflat surfaces II on the rotatable abutments I4 are spaced at a lessdistance from the axis of the shaft I2 than are the fiat surfaces I6.Consequently, on repetition of the broaching stroke of the breaches I4 afurther out will be made in the workpieces. The cycle may repeat itselfin this manner any desired number of times up to a maximum of twelvewhen the particular abutment fmeans'shown is employed.

' On each retraction of the table I6, the rotatable abutments I4 areindexed, and on the subsequent advancing movement of the table it movesto a slightly greater extent toward the broach than on the previousstroke due to the fact that cycle may be repeated, it should be notedthat twelve (12) abutment surfaces are provided on the rotatableabutments 14. Accordingly, if two workpieces are simultaneouslymachined, twelve (12) or less complete broaching cuts maybe made on eachworkpiece. It is, however, possible to operate themachine 'on a singleworkpiece at a time, taking a plurality of successive cuts on onebroaching tool and then shifting the workpiece to the second fixture andcompleting the cycle on the second or finish broaching tool. Theparticular hydraulic circuit mechanism hereinafter described is designedto provide a two-stage broaching operation on a single workpiece at atime in that manner. Accordingly, the machine automatically provides acycle of eleven (11) broaching strokes and then stops to permit theoperator to shift the workpiece from one fixture to the other. Then, onrestarting the machine it makes a single broaching cut on the workfixture with the finishing broach and again stops, whereupon theoperator removes the finished workpiece and places a new workpiece inthe first fixture, the parts then being in position to repeat thecomplete cycle.

It will be apparent that other variations in the sequence of operationof the machine may be made.

Regardless of the manner in which the machine is utilized, it will beapparent that during the last broaching stroke the parts will be in theposition illustrated in Figure 6, in which the flat surfaces 81 on therotatable abutments 14 engage the rod 60. On withdrawal of the tablefrom the position shown in Figure 6, which withdrawal completes theentire cycle of operation, the rotatable abutments 14 will be indexed inthe position shown in Figure 4, in which figure all parts are shown inposition to start a complete cycle. No claim is made herein to themechanical features of the machine so far described, as such are claimedin the application of Harry H. Gotberg, Serial No. 491,149, filed June17, 1943, now Patent No. 2,358,225, issued September 12, 1944. Thepresent invention relates primarily to the hydraulic circuit, thecircuit indexing features and the circuit control mechanism, shown bestin Figures 12 to 15, inclusive. Any desired form of adjustable abutmentmechanism may be employed with the circuit mechanism of Figure 12,although the mechanism shown in Figures 1 to 11 is preferred.

In Figure 12 is shown one form of hydraulic circuit which is adapted tooperate the machine automatically through eleven (11) successive cuttingstrokes and then stop the machine to enable the workmen to shift aworkpiece from the roughing fixture to the finishing fixture. When themachine is then manually started on its finish broaching stroke, itcompletes that stroke and retracts the table and again automaticallystops to enable removal of the finished workpiece and insertion of a newworkpiece. The parts are then inthe position to begin a complete newcycle of operation.

Referring to Figure 12, the main broaching slide cylinder is indicate atI2 and the cylinder for operating the table is indicated at 26. Fluid issupplied through suitable lines and valves to these two cylinders from apair of pumps I25 and I26, which are located within a tank or fluidreservoir I21. Pump-I25 supplies the broaching cylinder I2 through aline I28, a pilot control and overload by-pass valve I29, a line I30, aspeed control valve I30, a line I3I, and a pilot controlled four-Wayvalve I32 which has a pair of lines I33 and I34 leading to opposite endsof the cylinder I2. Line I34 is connected directly to the lower end ofcylinder IZthrough the piston rod I35, while line I33 connects to a footvalve I36 which, in turn, is connected to the upper end of the cylinderI2 by a line I31 and an auxiliary piston rod indicated diagrammaticallyat I38. In the actual construction, the two piston rods I35 and I38 areconcentric, and the fluid to the upper end of the cylinder flows betweenthe two rods.

Fluid from the pump I26 flows through line I40 to-a pilot controlledoverload relief valve MI and thence through line I42 to a pilotcontrolled fourway valve I43, which has apair of lines I44 and I45leading to thepiston rods 28 and 29, respectively, of the cylinder 26.The fluid which flows through piston rod 28 passes into the right-handend of the cylinder-26 through an opening I46, while the fluid flowingthrough the piston rod 29 flows into the opposite end of cylinder 26through an opening I41.

. The pilot controlled overload relief valve I20 provides a clear,unobstructed fiow between lines I28 and I30, and the stem I of the valvenormally closes the lower port, which is connected through line I5I andline I52 to the tank I21. Thestem I50 is provided with a piston I53,which fits the valve housing and which is provided with a small bleedopening I54. Accordingly, the pressure in lines I28 and I30 which existsin the main chamber of the valve housing I29 is transmitted through thebleed opening I54 in the piston I53 to the upper chamber of the valvehousing, thereby balancing the valve stem hydraulically. A light springI55 holds the balanced valve in its lower position, in which it closesthe port connected to 'line I5I.

The space above the piston I53 is connected through a passage I56 and aconnecting passage I51 to a ball check valve I58, which is normally heldin position to block passage I51 by the action of a spring I59. If thepressure in lines I28 and I30 exceeds a predetermined amount determinedby the setting of spring I50, the ball check valve I58 will open,thereby venting the fluid above piston I53 through a passage I60 andthrough an axial bore I6I in the valve stem to the tank lines I51 andI52. The flow of fluid through the bleed opening I54 is restricted; itcannot replace the fluid above the piston I53 as fast as it dischargesto the reservoir past the check valve I58. Consequently, the pressureabove the piston I53 will be less than that below the piston, and thevalve stem will move upwardly, opening the port connected to line I5I,This permits the fluid from pump I25 to discharge back to the tank atvery low pressure.

The stem I50 of valve I29 may also be caused to raise at any time duringthe operation of the machine by connecting pilot line I62 to the tankI21 in the manner hereinafter described. When this occurs, the pressureabove the piston I53 drops and the valve opens.

The valve I30 may be any suitable form of speed control valve. It is setto pass a desired portion of the fluid supplied to line I30 through lineI63 to the tank line I52, in order to decrease the speed of thebroaching stroke.

Except for its control upon the rate of flow of fluid to the maincylinder I2, the speed control valve I30 performs no function and can beomitted if desired, in which event line I30 would be connected directlyto line I3I.

The four-Way valve I32 is of the spring centered type, the spoolI66'being normally held in the position shown in the drawings by meansof a spring centering device including a. pair of washers I61 and I68loosely fitting the stem of the valve spool and a spring I69 whichsurrounds the stem and bears against the two washers. Washer I61 isadapted to bear against the righthand land of the valve spool I66, whilewasher I68 bears against sleeve I1 I, which is fixed to the valve stem.The washers also seat at their outer peripheries against shouldersformed on the valve casing.

When no pilot pressure is applied to either end of the valve the springcentering device shifts the valve spool to the positon shown, in whichposition fluid may flow from line I 3| into the am nular groove I13 andthence through notches I14 in the central land of the valve spool andthence through notches I15 in the right-hand land of the valve spool tochannel I16, which communicates through a passage I11 with the tank lineI52. Accordingly, no pressure is applied to line I34 in spite of thefact that it is in fluid communication with channel I13. The left-handland of the valve spool blocks return now from line I 33' to the tankline I52, which is also connected by means of passageway I11 in thevalve housing to annular channel I18.

When pilot pressure is applied to the righthand end of valve I32 throughpilot line I80, the valve spool is shifted to its left-hand end, duringwhich movement sleeve I1I compresses spring I 69. In its left-handposition, valve I32 permits flow of fluid under pressure from line I3Ito line I34, inasmuch as the notches I15 in the right-hand land areshifted out of registry with the channel I16 when the spool is in itslefthand position. In this position the left-hand land of the valvespool clears channel I18, with the result that fluid from line I33 mayreturn to the tank through channel I18, passageway I11 and tank lineI52.

When pilot pressure is admitted to the lefthand end of valve I32 throughpilot line I83, the central land of the valve spool shifts to the rightof channel I13, permitting flow of fluid under pressure from line I 3Ito line I33. Channel I18 remains closed by the left-hand land of thevalve spool, and the right-hand land of the valve spool clears channelI16, thus permitting return flow from line I34 through channel I16 andpassageway I11 to the tank line I52.

The foot valve I36 contains a spring pressed check valve I84 which isnormally held closed by a light spring I85, in consequence of which arelatively free flow of fluid is permitted through valve chamber I86,passageway I81, past check valve I84, through passageway I88 and valvechamber I89 to line I31,

Communication between valve chambers I99 and I86 is normally closed bymeans of the valve spool I90, which is held in its lower position bymeans of a spring I9I positioned within the hollow valve spool. Thevalve contains a third chamber I92, which is fitted by a piston I93 onthe valve spool I90, and 'a small bleed opening I94 connects chambersI89 and I92 at a point beneath the piston I93 in the latter chamber. Asa result of this construction, when line I33 is connected to the tankline I52 by valve I32 the pressure in line I31 from the upper end ofcylinder I2 will be communicated from chamber I89 through the bleedopening I94 to the lower portion of the chamber I92 beneath piston I93and tend to raise the valve spool. However, the spring I9I is asset thatitwill hold the valve spool closed against that pressure in line I31caused by the weight of the bro-aching slide but will permit the spoolto raise and open the valve at a slightly higher pressure. This preventsthe slide from falling by its own weight during the breaching stroke if,for any reason, the resistance to its downward movementdecreasessufficiently to permit it toso fall.

When the machine is not in the breaching or return strokes of its cycle,valve I32 assumes'its mid position shown in the drawings and therebyblocks return of fluid from line I33. This also prevents the cylinder I2from falling by gravity under these conditions.

The pilot controlled overload relief valve I41, which connects lines I40and I42, is identical in construction and mode of operation to the valveI29, previously described, and hence will not be described in detail.

It is sufficient to note that the valve I4I always permits free flowfrom line I40 to line I42; but if the pressure in lines I40 and I42exceeds a predetermined amount,'the valve spool will open, permittingdischarge of the fluid under pressure through line I96 to the tank lineI52. The spool of valve I may also be opened at any time during thecycle of operation by connecting pilot line I91 to the tank in themanner described in conneottion with valve- I29.

Four-way valve I43 is generally similar'to fourway valve I32 except thatthe spool of valve I48 is not spring centered but, on the contrary, isheld in either one of its two extreme" end'positions by means of aspring pressed detent 28!! which engages in either one 'of the pair ofnotches 20I and 202 in'the valve spool.

When pilot pressure is admitted to'the ri'glit hand end of valve I43through pilot line 205,'the spool is shifted to its left-hand position,shown in the drawings, in which position fluid under pressure from lineI42 flows between the central and right-hand lands on the valve spool toline I45 and thence to the left-hand piston rod29 of the work tablemoving cylinder. At thistime, fluid from the right-hand piston rod 28 ofthe work table moving cylinderreturns through line I44 and the spacebetween the left hand'and central lands of spool 203 to channel 206,which connects through a passageway201 to a line 208., Line 208, inturn, connects through line I96 to the tank linel52.

When pilot pressure is admitted to the lefthand end of valve I43 throughpilot line 209, valve spool 203 is shifted to its right-hand'position,in which position fluid under pressure from line I42 flows between thecentral and left-hand lands of the spool 203 to line I44. Return flowthrough line I45 passes between the central and rlghthand lands tochannel 2I0, which connects with passageway 201 and tank line 208.

When there is no pilot pressure applied to either end of valve I43, thevalve'spool is held against displacement from the position'it lastassumed by means of the spring pressed latch 200.

Operation of the above describedmain control valves to effect anautomatic cycle of operation of the machineis accomplished through apilot controlled valve system which includes three main control valvesanda number of auxiliary valves. Thethree main control valves are themanually operated control valves 2 I 5, a table operated pilot valve 2I6 for controlling the operation of the main breaching cylinder 12, anda dual breaching slide controlled pilot valve 2 I1-'-2I8 for controllingthe operation of the worktable,

The manual control valve 2I5 comprises a generally cylindrical bodyhaving a central bore provided wtih a plurality of axiallyspaced,"circumferential grooves 220; 22|, 222', 223, 224, 22s and 226.The-grooves 228 and 2.26 are simply to accommodate drainage, and have nofunction except to dispose of fluid which leaks past theend lands on thevalve spool. Slidable within the central bore is a valve spool 238,which i's-pro vided Withfour lands 23I, 232, 233 and 234. The spool isnormally .held' in the central or neutral position shown inthe drawingsby means of a spring 236, which bears-at one end against the bottom of acup-shaped sleeve 231 fixed to the right-hand end of the spool and atthe other end against a washer 231 which loosely surrounds the valvestem.

The outer periphery of the sleeve 231 has an annular wide recess 238 anda second narrow annular recess 239. A spring pressed'plunger248 isnormally urged into one or the other of the recesses 238 and 239. Thespool is shifted by means of an operating rod 242, which is connected toan operating handle 243 pivoted in a convenient place on the frame ofthe machine. When no pressure is applied to the handle 243, the spring236 shifts the sleeve 231, and consequently the spool 230, to theposition shown in the drawings'in which a spring pressed plunger 248engages the=left'- hand edge of the wide annular recess 238. When thehandle 243 is shifted to the left to start the machine, the Valve spoolis shifted by an amount equal to the width of the annular recess 238,with the result that when the operator releases the starting handle thespool is returned to its neutral position by spring 236. If the handle243 is shifted in a right-hand direction fromthe'neutral position,thespring pressed plunger 248 will engage in the annular recess 239andretain the spool in its right-hand positionnntil it is returned byoperation of the handle 243.

The table controlled pilot valve 2I6 has a generally cylindrical bodyhaving a central bore in which is provided a plurality of annularchannels 258, 25I, 252, 253 and 254.- Channels 258 and 254 are connectedby passageway 256 to a pilot line 251, which is connected; in turn, to apilot line 258 extending to the tank I21. Valve 2I6 is provided with aspool 268 having a pair of lands. The spool 268 is operated by means ofa rod-26L which is shifted in its left-hand direction, as viewed in thedrawings, by means of'a lever 26?. pivoted on a stationary portion ofthe machine and operatively connected to'the push rod 59 in the fixedabutment 56, shown best in Figure 4. Consequently, when the worksupporting table moves into broaching position, push rod 59 will beshifted to the right, causing movement of the valve spool 268' into itsleft-hand position.

When the work supporting table is fully retracted from broachingposition, as shown in Figure 12,. dog II8 engages lever II9, which,'inturn, shifts rod I2I to the right, rocking bell crank lever 264, whichis pivoted on' a stationary portion of the machine. Bellcrank"lever'-'264 operates a rod 265 which,'in turn, operates a bellcrank 266 in a clockwise direction. The upper arm of bell crank '266'isconnected to the rod 26Iby any suitable means, such as byproiecting intoa slot in the enlarged portion of rod 26I,so that clockwise rotation ofthe bell crank will shift rod 26I and spool 268 to their right-handposition, shown in Figure 12. The valve spool 2681s provided at itsright-hand end with a pair of grooves 268 and 269, which are adapted toreceive a spring pressed plunger 218 which operates to retain the spool268 in either one of its two adjusted positions.

The dual pilot valve 2H and 2I8 is, in reality, two'separate valvesmounted on a common operating shaft, indicated diagrammatically by theline 215. .The operating shaft 215 carries a pair of fingers 216 and211, which are adapted to be operated, respectively, by a pair of dogs218 and 219 mounted upon the broaching slide-I2. The fingers 216 and 211are displaced from each other transversely of the axis of thecylinder,,|2, and the dogs 218 and 219 are likewise so displaced; sothat the dog 218, which operates finger 216, will not engage finger-211,and dog 219, which operates finger 211, will not engage finger 216.

When the broaching slide I2 reaches its upper position, dog 218 engagesfinger 216 and rotates shaft 215 and, consequently, the rotary spools288 and 28I of the valves 2I1 and 2I8 in a clockwise direction, to theposition shown in Figure 12. With the spools'288 and 28! in the positionshown in the drawings, fluid may flow through valve 2I1 from port 282 toport 283 through a passageway 284 in the valve spool while ports 285 and286 are connected through passageway 293. At the same time, fluid willflow through valve-2I8 from port 288 to port 289 through passageway 298in the valve spool and ports 29I and 292 are connected throughpassageway 294.

When the broaching slide I2 reaches its lowermost position, the dog 219engages the finger 211 and rotates the shaft 215 and, consequently,valve spools 288 and 28I in a counterclockwise direction to a positionin which the flow through valve 2I1 is from port 282 to port 285 andports 283 and 286 are connected through passageway 293 in the spool. Atthe same time, the flow through valve 2I8 is from port 288 to port 29Iand from port 289 through passageway 294 to port 292.

It will be observed that port 285 of valve 2I1 is connected to the pilotline I 83 at the left-hand end of the four-way valve' I32 by means of apilot line 388 and a four-way reversing valve 38I. The flow through thefour-way reversing valve is normally'from port 382 through passageway383 in the rotatable valve spool 384 to port 385. It will also beobserved that port 289 of Valve 2I8 is connected to pilot line I88 atthe right-hand end of the four-way valve I 32 through a pilot line 389andthe four-way valve 38I, the fioW through the .valve 38I being fromport 3I8 to port 3| I and thence to the pilot line I88. The four-wayvalve 38I is normally maintained in the position shown in-Figure 12, butit will be observed that the pilot connections to the fourway valve I32which control the direction of movement of the broaching slide I2 may bere-- versed by shifting the four-way valve 38I to the right by means ofhandle 3I2, thus connecting port 362 to port 3 through passageway 383and connecting port 3 8 to port 385 through passageway. 3I3. Thisprovides a relatively simple means for reversing the broaching ram inthe event that the machine jams or otherwise stops during the broachingstroke.

Valve 3I6 is a combination check and pressure release valve, the purposeof which is to insure that the upper end of the broaching cylinder I2 isfilled and, therefore, the broaching cylinder is in its top positionbefore the work moving table begins to advance toward the broach. Toaccomplish this function valve 3I6; while it permits free flow from port3.I1 to port 3I8 through the spring pressed check valve 3I9, preventsreturn ,flow

.broaching cycle.

from port 3I8 to port 3I1 until the spool 326 is raised from theposition shown in the drawings. Spool 320 is normally held in its lowerposition by a spring 32I, and in that position it blocks flow betweenport 3| 1 and port 3I8 except as permitted by the check valve 3I9. Whenthe pressure in port 3I8 exceeds a predetermined value, the fluid fromport 3I8 which acts through passageway .322 on the plunger 323, raisesthe valve spool 320 against the action of spring 32I, and permits flowof fluid from port 3! 8 to port 3I1, under the circumstances hereinafterdescribed.

Valve 324 is a check valve connected by lines 325 and 325' between theport 3I8 of valve 3I6 and the main fluid line I 31 to the upper end ofthe cylinder I2. This check valve, which is similar in construction toValves 350 and 352, hereinafter described, permits free flow from line325 to line 325' but prevents reverse flow. Valves 3I5 and 324co-operate in a manner hereinafter described to preflll the upper end ofcylinder I2 before the work table can advance to breaching position.

Valve 326 contains a spool 321 having a land 323 which controlscommunication between ports 329, 333 and 33!. The position of the land328 determines whether or not the machine will stop at the end of abroaching cycle or will repeat the breaching cycle automatically. In theposition shown in the drawings, the land 328 blocks com municationbetween ports 329 and 330 and hence will cause the machine to stop atthe end of its If, however, the spool 321 is shifted to the right, thusproviding communica- 'tion between ports 329 and 330, the machine willautomatically repeat the breaching cycle until such time as the spool321 is shifted.

The position of the spool 321 iscontrolled by an indexing mechanismincluding a dog 334, wh ch is pivoted to a fixed portion of the machineand bears on a roller 335 on the stem of the valve spool 321. Theposition of dog 334 is controlled by engagement of a point 336 on thedog with the periphery of a disc 331. The disc 331 in the particularmachine illustrated is provided with a pair of notches 338 and 339. Aspring 340 bearing on the right-hand end of the valve spool 321 normallyurges the spool to the left and, when the disc 33! is in position forthe point 336 of dog 334 to fall into one of the notches 338 or 339, thespol 321 will shift to the position shown in the disc and cause stoppageof the machine. Disc 331 is fixed to a ratchet wheel 342 which, in'turn,is actuated by a pawl 343 carried by the rod 344 of a piston 345 in acylinder 346. Piston 345 is reciprocated once for each cycle ofoperation of the machine by the admission of fluid to the ports 341 and348, in the manner hereinafter described. A spring 349 acts to hold thepawl 343 at all times in engagement with the ratchet 342.

As previously indicated, valves MI and I29 may be opened at any time inthe cycle by connecting their respective pilot lines I91 and I 62 to thetank. Such valve opening is utilized to stop the machine in anemergency. Pilot line I62 is conby means of a line 355 and a line 356 tothe tank relatively light spring pressure to permit such flow, but theywill not permit flow in a reversed direction.

The operation of the hydraulic circuit is as follows. In Figure 12, allof the parts are shown in the position they assume at the end of acomplete cycle of operation of the machine, at which tme the machine isautomatically stopped to remove a finished workpiece and place a newworkpiece in one of the two work holding fixtures. Assuming that thepumps I25 and I26 are operating, there will be no pressure applied tothe breaching cylinder I2 because the main control valve I32 for thebreaching cylinder is in its central position, in which the pressurefluid supplied through line I3I flows to the tank through channel I13,notches I14, notches I15, channel I16, passageway I11, and tank lineI52. The fluid trapped in the up er end of cylinder I2 by valve I32 willhold the broaching cylinder in its upper position against the force ofgravity acting on the cylinder. The fluid under pressure from pump I26will be transmitted through line I40, valve I4I, line I42and valve I43to line I45 and thence to the left-hand end of the work cylinder 26through piston rod 29. Since the work table will be at its extreme outerposition and cannot move further, the pressure will "build up to a pointat which valve I4I will open,

venting the pressure from line I46 to the tank through lines I96 andI52.

The setting of valve MI is such that it lim ts the pressure in theleft-hand end of cylinder 26 during these circumstances to a safemaximum pressure. If at any time the pressure drops below the maximum,valve I4I will automatically close. In the meantime, high pressure ismaintained on line I42 and the left-hand end of cylinder 26.

The source of pilot pressure for the entire circuit is line 360, whichis connected to line I42 which at all times is subject to thepressuredeveloped by pump I26. Line 36!) connects to channel 252 ofvalve 2I6. When the machine is stopped in the position shown in thedrawings, the pressure from channel 252 is communicated from channel 253and thence to a line 36I which, in turn, is connected to port 282 ofvalve 2I1. Line 36I is also connected to the left-hand end of cylinder346, thus holding the piston 345 of the indexing mechanism in itsright-hand position. The pilot pressure from port 282 of valve 2I1 istransmitted through passageway 284 to port 283 and thence through line362 to the line 325, which extends between check valve 324 and port 3I8of valve 3I6.

Since no flow can occur between ports 3I8 and 3I1 of valve 316 until thepressure-has reached an amount determined by the setting, of valvespring 32I, the-pilot pressure from line 362 will pass upwardly fromline 325 through the check valve 324 to line I31 and thence to the upperend of the broaching cylinder I2 and help maintain the breachingcylinder in its uppermost position. If the machine is'left with the pumpmotor shut off for a substantial length of time, leakage will permit thecylinder I2 to sink downwardly under the influence of gravity and,accordingly, if that has occurred the flow from line 362 through line325 and check valve 324 will prefill the upper end of the cylinder andreturn the cylinder to its top position.

When cylinder I2 reaches its top position and can move no further, thepressure in the upper end of the cylinder in line I31, which acts onplunger 323 of valve 3I6 through passageway 322, will build upsuflicien-tly to overcome the force of spring 32I in valve 3I6, therebypermitting the valve to'open and provide communication between ports 3I8and 3I1. Spring 32I is so adjusted, however, that the valve openingcannot occur until the upper end of cylinder I2 is entirely filled andthe pressure increases in consequence of the fact that it can raise nofurther due to mechanical limitations.

When valve 3I6 opens, the pilot pressure then is transmitted from port3I1 through line 364 to a line 365, which extends to channel 225 ofvalve 2I5. At this point, the fluid is blocked so long as valve H5 is inits neutral position illustrated in the drawings. Communication is alsoprovided between pilot line 364 and port 329 of valve 326 by means of aline 366, but so long as the land 328 of valve 326 is in its stopposition, illustrated in the drawings, the fluid in line 366 and port329 is blocked and cannot flow to port 330 or line 368, which connectsport 330 to channel 223 of valve 2 I5. When valve 2I5 is in its neutralposition, pilot lines I62 and I91 from valves I29 and I4I, respectively,are also blocked at channel 22I of valve 2l5 and, consequently, thevalves I29 and MI will operate only as pressure relief valves. At thistime there is no pressure on either pilot line 205 or 209 of valve I43but the valve spool is retained-in its left-hand position by the springdetent 200. Likewise, pilot lines I80 and I83 of valve I32 are connectedto the tank,

The machine is started by shifting hand lever 243 to the left to itsstarting position. This shift moves valve spool 230 of valve 2I5 to theleft, opening communication between channels 225 and 224 and allowingthe pilot pressure in line 365 to flow through the valve to pilot line209 at the left-hand end of four-way valve I43. This pilot pressure willimmediately shift the valve spool 203 to its right-hand position.However, it should be noted that if the starting handle 243 is shiftedto starting position before the cylinder I2 is fully raised, valve 3I6will be closed, thus blocking communication between ports 3I1 and 3 I8and preventing any flow to the pilot line 365. Accordingly, valve 3I6positively prevents a shift of four-way valve I43 until the broachingcyliner I2 is fully elevated by the flow of fluid through line 325,valve 324, line 325, and line I31. As soon as the spool of valve I43shifts to its righthand position, the fluid under pressure in line I42is communicated through valve I 43 to line I44 and thence to theright-hand end of the work moving cylinder 26 through the piston rod 23and opening I46. This will cause the work table to advance the work intobroaching position, which position will be determined by engagement ofthe fiat surfaces 16 on the rotatable abutments 14 with the rods 60which, in turn, engage the fixed abutments 56.

As soon as the work cylinder 26 and the table driven thereby begintomove, the operator may release the starting handle 243, whereuponspring 236 will return the handle and valve spool 230 to their neutralposition, shown in the drawings. This will cut off the pilot pressure inpilot line 209 at the left-hand end of valve I43, but the spool 203 willremain in its right-hand position by reason of the engagementof thespring pressed detent 200 in notch 202.

5 Upon completion of the table advancing movement, push rod 59 will bemoved to the right by the rods 60 and will shift the spool 260 of valve2I6 t the left, thereby providing communication between channels 25I and252. Pilot pressure will then flow from line 360 through valve 2I6 toline 310, which is connected to channel 255 and thence to port 280 ofvalve 2I8. From port 288, the pilot pressure flows through passageway290 to port 289 and thence through line 309, port 3") of valve 30I, port3II of valve 30I, and line I80 to the right-hand end of the four-wayvalve I32. The pilot pressure in pilot line I80 will shift the spool I66of valve I32 to its left-hand position, thus connecting pressure lineI3I with line I34 and connecting tank line I52 with line I33. The fluidunder pressure in line I34 flows to the lower end of the broachingcylinder l2 and starts the downward or broachin stroke of the cylinder.During such broaching stroke the fluid in the upper endof the broachingcylinder returns through line I31, valve I36, line I33, valve I32, andthe tank line I52. At this time, the return flow of fluid through lineI31 will lift the spool I90 of valve I36 off its seat to permit thenecessary return flow.

It should be noted that the pilot pressure in line 310 which effectedthe last mentioned shift of the spool in valve 132 was not only directedto the port 288 of the valve 248, but also, by a branch line 312, to theright-hand end of cylinder 346 through the port 348, thus causing thepiston 345 to move to the left to retract the ratchet pawl 343.

It will also be observed that when the work table completed its movementand shifted valve spool 260 of valve 2I6, it caused a rocking movementof bell crank 266 'in a counterclockwise direction, thus returning thelever I I9 to its righthand position by reason of a connecting rod 265,bell crank 264, and rod I2 I.

Throughout the broaching stroke, fluid under pressure from pum I26 willbe maintained in the right-hand end of the work moving cylinder 26 eventhough the pilot pressure at the left-hand end of valve I43 iseliminated as the result of the shift of spool 260 in valve 2I6 as wellas the return of the starting handle to neutral position. This is due tothe fact that the spool 203 of valve I43 will be held in its right-handposition by engagement of the spring pressed detent 200 in the notch202, there being no pressure in either of the pilot lines 205 and 209 ofvalve 203 during the broaching stroke. Accordingly, the work fixturewill be held in position by the full operating pressure acting throughthe cam slot '23. The angle of the cam slot 23 is such that the pressurein the cylinder 26 required 'to hold the table in broaching positionagainst the maximum force exerted by the broach is less than thepressure required to shift the spool of valve I32 against the centeringspring I69. Consequently, the spool I66 will shift to its centralposition and stop the broaching stroke if for any reason the pressuredrops to a point where it is insuflicient to hold the table in broachingposition.

On completion of the broaching stroke of cylinder I2, dog 21-9 engagesfinger 211 and rotates the spools of valves 2I1 and 2I8 in acounterclockwise direction' to a position in which the pilot pressurethen existingin line 310 (spool 260 of valve 2l6 being in-its left-handposition) flows through port 288 of valve 2|=8 to port .291 of thatvalve and thence to the pilot line 205, which is connected at theright-hand endv of four-way valve I43. The pilot pressure in line 205will return the spool 203 of valve I43 to its left-hand position, shownin the drawings, thus causing the fluid under pressure from line I 42 topass through valve M3 to the line M5 and through pistonrod 29 andopening l4! to the left-hand" end of the work moving cylinder 26,thereby causing the work moving cylinder to retract the work table"until the cylinder assumes its fully retracted position, shown in thedrawings.

Upon completion of the retraction of. the work moving cylinder 26, dogH8 engages and shifts lever H9 to the position shown in the drawings,

thereby returning spool 260 of valve 2l'6 to its right-hand positionillustrated. In that position,

port 305 to pilot line r83, which is connected to the left-hand endofthe four-way valve F32.

The pilot pressure in line I83 shifts the spool I66 of valve t32 to itsright-hand position, in which fluid under pressure from line I31 passesto line I33 and thence through valve I36 and line l3 to the upper end ofthe breaching cyl ind'er l2 to cause the breach returning movement. Theflow at this time through the valve I36 is from chamber I86 throughpassageway I81 past the check valve [84 and through passageway I88 andchamber I89. During the breach returning movement, the fiui'din thel'ower end of the cylinder 12' returns through. line I34- and the valveI32 to the tank line I52.

At the time the breach returning movement is initiated, the pilotpressure then existing: in line 361 is not only transmitted toport 282of valve 211,v but also through branch line 361 to the left-hand end ofthe indexing cylinder 3413', thereby causing the piston 34-5 to movetothe right; carrying its ratchet pawl '3'43. This righthandmovemen't'o'f the pawl 343' returns the-pawl and piston 345* to theposition shownin the drawings and causes the ratchet wheel 342 and disc33F to' rotate clockwise one notch. This retationof the disc 33'!retracts the notch 339 out of engagement with the" oint- 336- on pivoteddisc 334; thereby causing the dog to'swing in a coun-' terclockwisedirection" and shift valve spool 321 of valve 326- to the right thusproviding communication between ports 329 and 330; As willhereatterbecome apparent; as long as ports 3-29- and 330 are incommunication witheach: other the machine will automatically repeat its: cycle ofoperations indefinitely.

As soon as broaching cylinder 12' reaches'the top of itsreturn stroke,dog 218- enga'ges finger 216, there'by'rotating: shaft 2 'l5'andspools2'80- and 281' of valves 2H and 218 in a clockwise direction;returning then to a position shown inthe drawings. Pilot pressure then:existing in line 36!- may then flowrrom port 282' of valve 2-] 1 throughpassageway 284 to port 283 and thence through line 362 to line 32 5.Ass'umingithat the cylinder I2 is in its extreme upward position, thefluid pressure in line 325 will then open valve 316, permitting a now offluidfrom port 318: to" port 31 1' and thence through line 33410 line366'; The

pilot'pressure in line 366 is transmitted toport; 329 of valve 323' andthence to'p'ort 33D' (land 328 having been shifted to the right) fromwhich it flows through line 368, channel 223 of valve 215, notches 315in land 2-33 of the valve spool 23!] to channel 224, which communicateswith the pilot line 209 for the left-hand end of four-way valve l l-'3.This pilot pressure in line 209 will shift the spool 283' to itsright-hand position inorder to initiate the work table advancingmovement of cylinder 26; thus beginning a new cycle automatically.

The new cycle will follow through in the manner previously described andthe piston 315 during such cycle, will operate to advance the pawl 343and ratchet wheel 342 through one additional notch in a clockwisedirection. The cycle will continue to repeat itself with the particularconstruetion shown eleven (11) times, or until the point 336 on pivoteddog 334 drops into notch 338 in the disc 331. This will occur during theeleventh broach returning movement, and will cause the spool 321 ofvalve 326' to shift to the left, into the position illustratedin thedrawings, in which position it blocks communication between ports 329and 330; When the eleventh broach return ing movement is completed, allof the parts of the hydraulic circuit except the ratchet wheel 342 anddisc 331- will be returned to the position shown advancing stroke aslightly greater distance toward the breach than on" the precedingadvancing stroke, as the result of the action ofthe surfaces 16 to 86,inclusive, on the rotatable abutments 14'. At the end of th'e eleventhcycle of operation, the surfaces ill on therotatableabutments M will bein alignment with the rods but out of engagement with the rods becauseof the fact that the table' willbe' retracted. Since the machine isstopped at this point, the operator may then shift the workpiece fromthe roughing fixture to the finishing fixture and, having done so, hemay againshift thelever 243 to its starting position; The machine willthen make a complete cycle of operation and again come to the stop; due'to the fact that the ratchetwheel 342 will have returned to the positionshown in the drawings, in which thepoint 336 of pivoted dog 334= restsin notch 339' of disc 331; At this stage, the finish broachin'g:operation will have been completed and all of the parts will have beenreturned to the positions shown in Figure 1 2. Thefinish'edworkpiecemay" then be removed from the machine and a new one inserted, andthe'machine' is ready to begin a completenew'cycle of operation.

It will be observed that if the line 364 were cor'm'ected directly topilot line 289; the machine would operate continuously without stopping.Instead"; line364 is connected toline 299'through two para'llel rOutesQeach containing a valve; One route is through the starting valve 2P5which blocks flow from 1ir'1e'364 t0line209: except when thehandle'243is held in itsstarting position. The other route is throughthe index valve 325* and valve 215. As l'ongi as the starti'ngvalve 2l 5is in its normalposition s-hovvn a rfd the pivoted dds is not engagingin anotch in disc 331; index valve into a scream disc 331, valv'e326bl'ock's com munication and the machine stops at theend of the broachreturn movement.

It should also be noted that when the valve 328 blocks communicationfrom line 334 to line 299 it connects line 299 to thetank. This isnecessary in order to permit a shift of the spool of valve I43 to theleft 'whenboth of the valves 2l5 and 326 are in the position shown inthe drawings. This situation arises during the first cycle after themachine is started by manually operated valve 215 and the dog 334 is ina notch in disc 331. The connection from line 289 to valve326 is madethrough valve 215 in order that the connection can be blocked when valve325 is in its stop position shown and valve 2 l 5 is shifted to itsstarting position. Otherwise at that time line 209 would be connected tothe tank by valve 326 and no pilot pressure would build up in line 299to shift valve I43.

In multiple stroke broaching machines of the type to which the presentinvention relates it is desirable to perform the preliminary or.roughing cuts on the work without permitting the finishing teeth of thebroach to contact the work. Then, following the oughing cuts, a singlefinishing stroke of greater length is made during which time thefinishing teeth perform their finishing operation. This arrangementsaves wear and tear on the finishing teeth and enables the broach to cutto correct depth for a substantially longer period of time. Accordingly,there is provided, as best shown in Figures 13 to 15, an attachmentwhich may be incorporated in the machine previously described in orderto effect this result.

Referring to Figure 14, there is shown the shaft 215 which, as indicateddiagrammatically in Figure 12, controls dual valve 2l1-2 [8. In themachine of Figures 1 to 12, shaft 215 has fixed thereto a pair offingers 216 and 211 adapted tobe operated by the trip dogs 218 and 219on the main breaching ram. In the modified construction similar tripdogs 218 and 219are provided, as best shown in Figures 14 and 15, foroperating corresponding fingers 216' and 211'. However, the fingers 216and 211, instead of being fixed to the valve shaft 215, are formed upona boss 389, which is secured to the shaft by means of a pin 38l pressfitted into the boss 388 and extendin through a slot 382 formed in theshaft 215 near its forward end. The forward end of the shaft 215 in themodified construction is provided with an axial bore 383, and a springpressed plunger 384 slidable within the bore engages the central por-'tion of the pin 38! and normally holds the boss' 389 in its outermostposition, in which position the finger 216 is in position to be engagedby the trip dog 218, but thefinger 211 is displaced for'-' wardly of thepath of movement of the trip dog 219 and lies in the path of movement ofa third trip dog 386.

The trip dogs 218, 219 and 383 are secured to the face of the ram in theusual manner; that is to say, the trip dog 218 is secured to the face'ofthe ram near its lower end, while the trip dog 219 is slidably fixed ina 'bar 381 secured to the ram. The

trip dog 219 is secured to the bar by means of a' T-slot 388 formed inthe bar and a cooperating T-bolt 388' extending through the'dog with itshead in the T-slot. 'As a result of this arrangement, the position ofthe trip dog 219 can be ad justed in order to adjust the length of thebroaching stroke.

The additional trip dog 383 provided in the modified construction islikewise secured in the T-slot 388 of the bar 391 in the same mannen'butis cated a point below the tripdog 219. As aresult of this arrangement,duringth'e'roughing strokes the auxiliary trip vdog 389 will engage thefinger 211', thus shifting the, dual valve 2l1-12l8, of

Figure 12 and thereby bringing the ram to a stop and starting the workwithdrawal stroke of the table, in themanner previously described inconnection with Figure 12. Trip dog 386 is so. positionedthat thestoppage of the ram will occur just before the finishing teeth of thebroach engage the work.

As is the usual practice, a spring pressedrflunger 389 carried by a'stationary portion of the machine is adapted to engage in a pair ofslots in the boss 380 to hold the boss against accidental displacementfrom either of its two rotative positions.

The machine will thus continue to operate automatically through thedesired number of roughing strokes in the mannerv previously described,during which time the work table will be fed toward the broach to agreater degree before each succeeding stroke, until during the lastroughing cut of each complete cycle the work fixture 39 occupies theposition shown in Figures 13 and 14, in which position the extremity ofa cylindrical bar 390 fixed to the work fixture engages the end of theboss 389 in the manner illustrated in the I drawings.

40 last roughing cut the bar 399zwill just contact the boss 380 carryingthe fingers 216 and 211' without displacing the boss to the right, asviewed in Figure 14. However, on completion of the last roughing cut andprior to the finishing stroke of the machine the work table will beretracted and again advance, this time to a greater extent than thatindicated in Figures 13 and 14. During this further advance the bar 399will engage boss 399 and shift the boss to the right until the tripfinger 211' is out of the path of trip dog 386 and in the path of tripdog 219. It will be noted that the outer end of the bar 390 is providedwith a bore 396 to accommodate the end of shaft 215 during this movementof the boss 389.

As a result of this shift of the boss 399, the broaching ram will make acomplete stroke, thus carrying the finishing teeth of the broach-pastthe work for the first time, and stoppage of the ram will be effectedbyengagement of the tripdog 219 with the finger 211'. .Upon'completionofthe finishing stroke the work table will be again retracted in themanner previously described, thereby' permitting the boss 380 to returnto the position shown in Figures 13 and 14. Consequently, when the rammakes its'broach return stroke the trip dog 218 will engage finger 216and bring the machine to a stop at the end of the complete cycle.

It will be apparent. that the modification of Figures 13 to 15 may beapplied to the machine With this attachment the-machine previously de-jscarrescr ibed will operate to-make-the complete broachcycle; I-t willbe obvious, however, that this feature isrequired only when the completebroaching cycle performed upon the workpiece by the same broach. Thus itis not required if a special finishing broach is provided onthe ram andthe work is shifted upon completion of the roughing cuts into a positionin which it will engage the finishing broach. Accordingly, when theattachment of- Figures 13 to 15 is employed, the machine of Figures 1 to12 will perform the complete breaching cycle on two workpiecessimultaneously and thenotch 3-38- providedin the disc 33'! of, Figure12, which brings the machine to a stop upon completion of the roughingstroke, may be omitted; The attachment, therefore, has the effect ofdoubling the productive capacity of the machine;

It' will be apparent that there is provided in accordance with thepresent invention an improved and simple hydraulic indexing circuit,particularly adapted for use in a machine for making a plurality ofsuccessive breaching cuts in a single workpiece. While only a singleembodiment of the invention is shown and described, it will be apparentthat others are available within the spirit of the invention and thescope of the appendedclaims.

'What is claimed is:

I. In an automatic multiple stroke hydraulic broaching machine, abroaching ram, a reciproeating work fixture, hydraulic means for automatically operating the ram and fixture through a plurality of broachingcycles each including in succession an advance of the fixture tobroaching position, a broaching stroke of the ram, withdrawal of thefixture from broaching position and return of. the ram, means forcausing the fixture to-advance to a greater extent, toward the broachonleach. of said plurality of cycles, said hydraulic means includingcontrol valve means adapted whenshifted in oneidirection to bring theram to a. stop when it is moving in its broa'ching direction. and toinstitute withdrawal of the fixture, a movable element for shifting saidvalve means in said direction, a cooperating element carried byjthebroaching ram and normally adapted to engage said first element duringmovementof the ram in broaching direction and thereby shift said valvemeans in said direction before the finishing teeth of the broach haveengaged the work, means on said fixture for engaging one of saidelements and shifting it in a direction to prevent engagement with theother element when the fixture has moved at predetermined distancetoward the breach, and means operable to engage said movable element andthereby shift the valve means a in said. direction when the finishingteeth of the broacir on each of said plurality ofcycles, saidhydraulicmeans including control valve means adapted when shifted in onedirection to bring the ram to a stop-when it is moving in its broachingdirection-and to institute withdrawal? of the fixture, a movable elementfor shifting said valve means in said direction, a pair of trip dogsfixedto the ram for movement therewith inparallel paths, said elementbeing normally in the path; of movement of one of said dogs whereby saiddog will engage the element during movement of the ram inbreaching-direction and therebyshi'ft said valve means in saiddirection, said onedog being so located alongthe length of the ram as toengage the element before the finishing teeth of the broach engage thework, and means on said fixture for engaging said element and shiftingthe same out ofthe path ctr-movementof said one dog into the path ofmovement of the other dog when the fixture has moved a piledetermineddistance-toward the broach, said other dbgbeing so locatedalong the length of the mm as to engage the element when the finishingteeth of the broach have passed over the work;

3. In an automatic multiple stroke hydraulic b'roaching' machine, abreaching ram, a reciproeating work fixture, hydraulic means forautofixture, a rotatable shaft for shifting said valve means in saiddirection, means having a substantially radial projection rotatable withsaid shaft, a projection on said ram normally adapted to engage theprojection on the shaft during" movement of the ram in breachingdirection and thereby rotate said shaft to shift the valve means I insaid direction before the finishing teeth of until it will no longerengage the other element when the fixture has moved a predetermineddistance toward the breach, and means operable to engage said projectionon the shaft and thereby shiftsaid valve means in said direction whenthe finishing teeth of the broach have passed over the work.

4. In an automatic multiple stroke hydraulic broaching machine, abroaching ram; a reciprocating work fixture, hydraulic means forautomatically operating the ram and fixture through a plurality ofbreaching cycles each including in succession an advance of thefixture'to broaching position, a broaching stroke of the ram, withdrawalof the fixture from broaching position and return of the ram, means forcausing the fixture to advance to a greater extent toward the broach oneach of said plurality of cycles, said hydraulic means including controlvalve means adapted when shifted in one direction to bring the ram to-astop when it is moving in its broaching direction and toinstitutewithdrawal of the fixture, a rotatable shaft for shifting said valvemeans in said direction, means fixed."

against rotation with respect to but axially slidable with respect tosaid shaft, said means including a substantially radially projectingfinger,

a pair of trip dogs fixed to the ram and movable therewith in parallelpath's, resilient means normally holding said first mentioned means inthe path of movement of one of said dogs, said one dog being adapted toengage said finger and thereby rotate the shaft and shift said valvemeans in said direction when the ram is moving in its breachingdirection and before the finishing teeth of the broach engage the work,and means on the fixture adapted to engage said first means and shift itaxially until the finger is in the path of movement of the other dogwhen the fixture has moved a predetermined distance toward the broach,said other dog being adapted to engage the finger after the finishingteeth of the breach have passed over the work.

5. In a hydraulically operated machine having a plurality ofhydraulically operated mechanisms adapted to operate automaticallythrough a plurality of complete cycles of operation, the operation ofone of which mechanisms is instituted by admission of pilot pressure toa pilot controlled valve associated with said one mechanism, thecombination of a pilot line for supplying pilot pressure to said valve,a control means for said machine associated With said pilot line, saidmeans including an index valve in said line and an indexing mechanismfor shifting said index valve into a position in which it blocks assageof fluid through said pilot line, and means forefiecting an incrementalmovement of said indexing mechanism toward the position in which iteffects said shift of the index valve once during each cycle ofoperation of said machine whereby said valve will be so shifted afterthe machine has completed a predetermined number of complete cycles ofoperation.

6. In a hydraulically operated machine having a plurality ofhydraulically operated mechanisms adapted to operate automaticallythrough a plurality of complete cycles of operation, the operation ofone of which mechanisms is instituted by admission of-pilot pressure toa pilot controlled valve associated with said one mechanism, thecombination of a pilot line for supplying pilot pressure to said valve,a control means for said machine associated with said pilot line, saidmeans including an index valve in said line, an indexing mechanism forshifting said index valve into a position in which it blocks passage offluid through said pilot line, and means for effecting an incrementalmovement of said indexing mechanism toward the position in which iteffects said shift of the index valve once during each cycle ofoperation of said machine whereby said valve will be so shiftedafter'the machine has completed a predetermined number of completecycles of operation and manually operated means to cause flow throughsaid line independently of said indexing mechanism.

- '7. In a hydraulically operated machine having a plurality ofhydraulically operated mechanisms adapted to operate automaticallythrough a plurality of complete cycles of operation, the operation ofoneof which mechanisms is initiated by admission of pilot pressure to apilot controlled valve associated with said mechanism,

the combination of a pilot line for supplying pilot pressure to saidvalve, a control means for said machine associated with said pilot line,said means including a manually operable valve and an index valve forcontrolling flow of pilot fluid through said line, said index valvebeing operable to permit flow through said line when the manuallyoperable valve is closed, an indexing mechanism for actuating said indexvalve to cause said index valve to block the flow of pilot fluid underpressure through said line to said pilot operated valve, and means foreffecting an incremental movement of said indexing mechanism toward theposition in which it efiects said actuation of the index valve onceduring each cycle of operation of said machine whereby said valve willbe so actuated after the machine has completed a, predetermined numberof complete cycles of operation, said manually operable valve beingnormally closed but effective when opened to permit flow of pilot fluidthrough said line when the index valve is in blocking position.

8. In a hydraulically operated machine havin a source of liquid underpressure, a low pressure reservoir and a plurality of hydraulicallyoperated mechanisms adapted to operate automatically through a pluralityof complete cycles of operation, the operation of one of whichmechanisms is initiated by admission of pilot liquid under pressure to apilot controlled valve associated with said mechanism, the combinationof a pilot line for conducting pilot liquid to and from said valve, acontrol means for said machine associated with said pilot line andeffective to control communication between said line and said source ofliquid under pressure and said reservoir, said means including amanually operable valve and an index valve associated with said line,said index valve being operable to connect said line to said pressuresource when the manually operable valve is closed, said manuallyoperable valve being normally closed but effective when opened toconnect said line to said pressure source regardless of the position ofthe index valve, an indexing mechanism for actuating said index valve tocause said index valve to block the flow of pilot fluid under pressurethrough said line 4Q to said pilot operated valve, and means forefiecting an incremental movement of said indexing mechanism toward theposition in which it effects said actuation of the index valve onceduring each cycle of operation of said machine whereby said valve willbe so actuated after the machine has completed a predetermined number ofcomplete cycles of operation, said control means including means forconnecting said line to the low pressure reservoir when both saidmanually operable valve and said index valve are closed to prevent flowof pilot liquid under pressure to said pilot operated valve.

9. In a hydraulically operated machine having a plurality ofhydraulically operated mechanisms adapted to operate automaticallythrough a plurality of complete cycles of operation, the operation ofone'of which mechanisms is initiated by admission of pilot fluid underpressure to a pilot controlled valve associated with said mechanism,thecombination of a pilot line for conducting pilot liquid to and fromsaid valve, a control means for said machine associated with said pilotline, said means including a by-pass line connected in parallel with aportion of said line, a manually operable valve in said line efiectivein its normal position to block communication through said line and opencommunication through said by-pass line and effective in anotherposition to open communication through said line and block communicationthrough said by-pass line, an index valve in said by-pass line effectivein one osition to block flow of pilot fluid insaid by-pass line towardsaid pilot operated valve and to permit unrestricted flow of fluid fromsaid pilot operated valve and effective in another position to permitflow in either direction through said by-pass line, an indexingmechanism for "controlling the position of said index valveand effectiveto shift said index valve to said first ..menti'oned position, and

means for effecting an incremental movement of said indexingmechani'smtoward the position in which it effects said shifthof the index valve tosaid first mentioned position once during each cycle of operation of.said'machine, whereby said valve will be shifted to said first mentionedposition after the machine has completed a predetermined number ofcomplete cycles of operation.

10. In a hydraulic broaching machine, a pilot operated valve-forcontrolling the flow of fluid to and from a broach moving piston andcylinder mechanism, a second pilot operated valve for controlling theflow of fluid-to and. from a piston and cylinder mechanism for operatinga work holding table, means including pilot valves controlled by theositions of said mechanisms for actuating said pilot operated valves toeffect a plurality of complete cycles of operation each including insuccession advance of the table mechanism, a broaching stroke of thebroach, return of the table mechanism and return of the broach,auxiliary control means connected in the pilot line to that end of thesecond pilot operated valve which, when connected to a source of pilotpressure, shifts said valve to table advancing position for controllingthe flow of pilot fluid in said line, said means including anindex valvein said line and an indexing mechanism for shifting said valve into aposition in which it blocks flow of pilot fluid under pressure throughsaid line to said second pilot operated valve, and means for effectingan incremental movement of said indexing mechanism toward the positionin which it effects said shift of the index valve once during each cycleof operation of said machine whereby said valve will be so shifted afterthe machine has completed a predetermined number of complete cycles ofoperation.

11. In a hydraulic broaching machine, a ilot operated valve forcontrolling the flow of fluid to and from a broach moving piston andcylinder mechanism, a second pilot operated valve for controlling theflow of fluid to and from a piston and cylinder mechanism for operatinga work holding table, means including pilot valves controlled by thepositions of said mechanisms for actuating said pilot operated valves toeffect a plurality of complete cycles of operation each including insuccession advance of the table mechanism, a broaching stroke of thebroach, return of the table mechanism and return of the broach, andauxiliary control means connected in the pilot line to that end of thesecond pilot operated valve which, when connected to a source of pilotpressure, shifts said valve to table advancing position for controllingthe flow of pilot fluid in said line, said means including an indexvalve in said line, an indexing mechanism for shifting said valve into aposition in which it blocks flow of pilot fluid under pressure throughsaid line to said second pilot operated valve, means for effecting anincremental movement of said indexing mechanism toward the position inwhich it effects said shift of the index valve once during each cycle ofoperation of said machine whereby said valve will be so shifted afterthe machine has completeda predetermined number of complete cycles ofoperation and manually operated means to cause flow through said lineindependently of said index valve.

1 In a hydraulic broaching machine, a pilot operated valve forcontrolling the flow of fluid to and from a broach moving piston andcylinder.

mechanism, a second pilot operated valve for controlling theflow offluid 'to and from a piston and cylinder mechanism for operating a workholding table, means including pilot valves controlled by the positionsof saidmechanisms for actuating said pilot operatedvalves to effect aplurality of complete cycles of operation, each including in successionadvance of the table mechanism, a broaching stroke of the broach, returnof-the table mechanism and return of the broach, and auxiliary controlmeans connected in the pilot line to that end of the second pilotoperated valve which, when connected a source of pilot pressure,

shifts said valve to table advancing position for controlling the flowof pilot fluid in said line, said means including a normally closedvalve manually operable to permit flow through said line, an index valveoperable to permit flow through said line when themanually operablevalve is closed, an indexing mechanism for actuating said index valve tocause said valve to block the flow of pilot fluid under pressure throughsaid line to said pilot operated valve, and means for effecting anincremental movement of said indexing mechanism toward the position inwhich it effects said actuation of the index valve once during eachcycle of operation of said machine whereby said valve will be soactuated after the machine has completed a predetermined number ofcomplete cycles of operation.

13. In a hydraulic broaching machine, a pilot operated valve forcontrolling the flow of fluid to and from a broach moving piston andcylinder mechanism, a second pilot operated valve for controlling theflow of fluid to and from a piston and cylinder mechanism for operatinga work holding table, means including pilot valves controlled by thepositions of said mechanisms for actuating said pilot operated valves toeffect a plurality of complete cycles of operation, each including insuccession advance of the table mechanism, a broaching stroke of thebroach, return of the table mechanism and return of the broach, andauxiliary control means connected in the pilot line to that end of thesecond pilot operated valve which, when connected to a source of pilotpressure, shifts said valve to table advancing position for controllingthe flow of pilot fluid in said line, said means including a normallyclosed valve manually operable to permit flow through said line, anindex valve operable to permit flow through said line when the manuallyoperable valve is closed, an indexing mechanism for actuating said indexvalve to cause said valve to block the flow of pilot fluid underpressure through said line to said pilot operated valve, and means foreffecting an incremental movement of said indexing mechanism toward theposition in which it effects said actuation of the index valve onceduring each cycle of operation of said machine whereby said valve willbe so actuated after the machine has completed a predetermined number ofcomplete cycles of operation, said control means being adapted to permitreturn flow of pilot fluid from that end of said pilot operated valve towhich said line is connected when both said manually oper-' able valveand said index valve are closed to prevent flow of pilot fluid to saidend of said pilot 1 operated valve.

14. In a hydraulic broaching machine, a pilot operated valve forcontrolling the flow of fluid to and from a broach moving piston andcylinder mechanism, a second pilot operated valve for controlling theflow of fluid to and from a piston and cylinder mechanism for operatinga work holding table, means including pilot valves controlled by thepositions of said mechanisms for actuating said pilot operated valves toefiect a plurality of complete cycles of operation, each including insuccession advance of the table mechanism, a breaching stroke of thebroach, return of the table mechanism and return of the broach, andauxiliary control means connected in the pilot line to that end of thesecond pilot operated valve which, when connected to a source of pilotpressure, shifts said valve to table advancing position for controllingthe flow of pilot fluid in said line, said means including a by-passline connected in parallel with a portion of said line, a manuallyoperable valve in said line effective in its normal position to blockcommunication through said line and open communication through saidby-pass line and effective in another position to open communicationthrough said line and block communication through said by-pass line, anindex valve in said lby-pass line effective in one position to blockflow of pilot fluid in said by-pass line toward said pilot operatedvalve and to permit unrestricted flow of fluid from said pilot operatedvalve and effective in another position to permit flow in eitherdirection through said by-pass line,

an indexing mechanism for controlling the posi- BENEDICT WELTE.

